全文获取类型
收费全文 | 1943篇 |
免费 | 113篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 54篇 |
妇产科学 | 41篇 |
基础医学 | 318篇 |
口腔科学 | 7篇 |
临床医学 | 200篇 |
内科学 | 465篇 |
皮肤病学 | 19篇 |
神经病学 | 220篇 |
特种医学 | 43篇 |
外科学 | 170篇 |
综合类 | 19篇 |
一般理论 | 4篇 |
预防医学 | 221篇 |
眼科学 | 16篇 |
药学 | 130篇 |
1篇 | |
肿瘤学 | 121篇 |
出版年
2023年 | 10篇 |
2022年 | 11篇 |
2021年 | 39篇 |
2020年 | 22篇 |
2019年 | 14篇 |
2018年 | 48篇 |
2017年 | 20篇 |
2016年 | 20篇 |
2015年 | 27篇 |
2014年 | 38篇 |
2013年 | 61篇 |
2012年 | 113篇 |
2011年 | 131篇 |
2010年 | 63篇 |
2009年 | 84篇 |
2008年 | 155篇 |
2007年 | 163篇 |
2006年 | 115篇 |
2005年 | 125篇 |
2004年 | 121篇 |
2003年 | 111篇 |
2002年 | 108篇 |
2001年 | 50篇 |
2000年 | 26篇 |
1999年 | 42篇 |
1998年 | 16篇 |
1997年 | 20篇 |
1996年 | 26篇 |
1995年 | 17篇 |
1994年 | 12篇 |
1993年 | 12篇 |
1992年 | 24篇 |
1991年 | 13篇 |
1990年 | 19篇 |
1989年 | 17篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1979年 | 16篇 |
1978年 | 8篇 |
1976年 | 18篇 |
1974年 | 6篇 |
1973年 | 4篇 |
1968年 | 4篇 |
排序方式: 共有2060条查询结果,搜索用时 15 毫秒
11.
The genome of equine arteritis virus (EAV) produces a 3 coterminal-nested set of six subgenomic (sg) viral RNAs during virus replication cycle, and each set possesses a common leader sequence of 206 nucleotides (nt) in length derived from the 5 end of the viral genome. Given the presence of the leader region within both genomic and sg mRNAs, it is likely to contain cis-acting signals that may interact with cellular or viral proteins for RNA synthesis. Gel mobility shift assays indicated that proteins in Vero cell cytoplasmic extracts formed complexes with the positive (+) and negative (-) strands of the EAV leader RNA. Several cell proteins with molecular masses ranging from 74 to 31 kDa and 58 to 32 kDa were detected in UV-induced cross-linking assays with the EAV leader RNA (+) and (-) strands, respectively. In both cases, intense bands were observed at the 58–52 kDa molecular weight markers. Results from competition gel mobility shift assays using overlapping cold RNA probes spanning the leader RNA (+) strand indicated that nt 140–206 are not necessary for binding to cell proteins. 相似文献
12.
The amygdala are thought to play an important role in emotional information processing. First studies indicate a link between amygdala atrophy, fear and aggression and between amygdala hypertrophy and depression. To investigate a possible relationship between amygdala volumes, aggression and depression, we measured the amygdala of 62 patients with temporal lobe epilepsy (TLE) with and without aggressive behavior or depression and 20 healthy volunteers using quantitative magnetic resonance imaging (MRI). Amygdala volumes of female patients (n=26) were significantly larger than those of males (n=36) (left side: P=0.001; right side P=0.05). Depressed patients displayed significant enlargement of both amygdala (left side: P=0.008; right side: P=0.001) There was no significant finding relating to the factor aggression neither was there any significant interaction between aggression, dysthymia and gender. 相似文献
13.
Anne-Laure Bauchet Laëtitia Elies Pierre Maliver Marie-Claude Fouque Emmanuelle Balme Sophie Chteau-Joubert Frdric Schorsch Jean-Jacques Fontaine 《Experimental and toxicologic pathology》2008,60(4-5):307-311
Mammary gland adenomyoepitheliomas are benign complex mammary gland tumors composed of neoplastic cells of epithelial and myoepithelial origins, described in many species (humans, dogs, cats, rats) and rarely in mice. We report here an adenomyoepithelioma in a C57BL/6 female mouse. Histologically, tubes and cords formed by neoplastic epithelial cells were separated by bundles of neoplastic myoepithelial cells in a clear and partially mucinous matrix. The tumor displayed characteristics of a benign neoplastic proliferation with a compressive growth pattern, and moderate cellular pleomorphism and mitotic index. At immunohistochemistry, the epithelial cells were strongly cytokeratin positive; the myoepithelial cells were weakly cytokeratin positive and strongly smooth muscle actin positive. This is to our knowledge, the first report of a mammary gland adenomyoepithelioma in a C57BL/6 mouse. 相似文献
14.
Phenotypic characterization of two cell populations involved in the acquisition of suppressor activity by cultured spleen cells from Mycobacterium lepraemurium-infected mice. 下载免费PDF全文
The impairment of cellular immunity in mice infected with Mycobacterium lepraemurium was shown to correlate with the development of suppressor cells. We have previously reported that before suppressor activity is detectable in freshly harvested cell suspensions, suppressor cell precursors accumulate in the spleen of infected mice. Upon overnight culture in the presence of a regulatory cell subset, these precursor cells acquire the capacity to impair the concanavalin A (Con A)-induced proliferation of normal spleen cells. The purpose of this study was to determine the phenotype of the cells involved in this phenomenon. This was done by following the development of suppressor activity in spleen cell suspensions depleted of defined cell subsets of the adherent or the non-adherent cell fractions with selected MoAbs and immunomagnetic beads or by in vivo treatment. Our results indicate that the acquisition of suppressor activity requires the interaction of Ia+CD11b+Fc gamma R+IgG- asialo GM1- adherent cells with Thy1-CD4-CD8-IgG-Ia- asialo GM1-Fc gamma R+CD11b+ non-adherent cells. It is also shown that the development of suppressor activity is impaired by preventing cell-cell contact between these two cell subsets through coculture in 'Transwell chambers'. These observations support the conclusion that the in vitro acquisition of suppressor activity is a consequence of the maturation of suppressor cell precursors of the monocytic lineage induced by a receptor-ligand type interaction with a non-adherent cell subset that is clearly distinct from mature T, B and natural killer (NK) cells. 相似文献
15.
Effect of dosage on immunogenicity of a Vi conjugate vaccine injected twice into 2- to 5-year-old Vietnamese children 总被引:2,自引:0,他引:2 下载免费PDF全文
Canh DG Lin FY Thiem VD Trach DD Trong ND Mao ND Hunt S Schneerson R Robbins JB Chu C Shiloach J Bryla DA Bonnet MC Schulz D Szu SC 《Infection and immunity》2004,72(11):6586-6588
In a double-blind, randomized, and placebo-controlled previous trial, the efficacy of Vi-rEPA for typhoid fever in 2- to 5-year-olds was 89.0% for 46 months. Vi-rEPA contained 25 microg of Vi and induced a greater-than-eightfold rise in immunoglobulin G (IgG) anti-Vi in all of the vaccinees tested. In this investigation, we conducted a dosage-immunogenicity study of 5, 12.5, and 25 microg of Vi-rEPA in this age group. Two doses of Vi-rEPA were injected 6 weeks apart. Blood samples were taken before and at 10 weeks (4 weeks after the second injection) and 1 year later. All postimmunization geometric mean (GM) levels were higher than the preimmune levels (P < 0.0001). At 10 weeks, the GM IgG anti-Vi level elicited by 25 microg (102 EU/ml) was higher than those elicited by 12.5 microg (74.7 EU/ml) and 5 microg (43 EU/ml) (P < 0.004): all of the children had > or = 3.52 EU/ml (estimated minimum protective level). One year later, the levels declined about sevenfold (13.3 and 11.3 versus 6.43 EU/ml, P < 0.0001) but remained significantly higher than the preimmune levels (P < 0.0001), and >96% of the children had a greater-than-eightfold rise. This study also confirmed the safety and consistent immunogenicity of the four lots of Vi-rEPA used in this and previous trials. 相似文献
16.
Long A Tremblay L Richard L Lemieux R Goldman M 《Immunohematology / American Red Cross》2002,18(4):120-122
Low concentrations of sodium hypochlorite (chlorine bleach) are known to destroy S antigen on intact fresh red blood cells (RBCs). Sodium hypochlorite is commonly used as a disinfectant. We report nondetection of the S antigen in tube and microplate saline indirect antiglobulin testing (SIAT) with a lot of commercial saline utilized in our donor screening and reference laboratories. Known S+s+ RBCs were found to be nonreactive with anti-S by SIAT in our reference laboratory. Our investigation demonstrated the presence of chlorine in the commercial saline. The saline lot was used for several days of donor screening and recall of FFP and platelet concentrates was initiated. Two lots of saline were recalled from blood banks across North America. 相似文献
17.
Christelle Faveeuw Marie-Claude Gagnerault Fran?oise Lepault 《Clinical & developmental immunology》1994,3(4):273-282
Subpopulations of lymphoid cells were compared with respect to their ability to migrate into
peripheral lymphoid organs of nonobese diabetic (NOD) mice and various strains of control
mice. In short-term, in vivo homing studies, no major differences in the pattern of homing
of B and T cells were observed among all mouse strains studied. On the other hand, CD4
cells localized consistently more efficiently than CD8 cells in both PP and LN of adult NOD
and BALB/c mice, whereas both populations migrated roughly equivalently in LN of adult
DBA/2, CBA, and C57BL/6 mice. No age-dependent differences in the homing of CD4 and
CD8 cells were observed in BALB/c mice. On the contrary, in 2-week-old NOD mice, CD4
and CD8 cells migrated equally well. The preferential entry of CD4 cells in adult NOD and
BALB/c did not result from increased blood transit time of CD8 cells. On the other hand,
the preferential migration of CD8 cells was observed in the liver, whereas the two T-cell
subsets migrated equally well in the lungs. The differences in the homing characteristics of
CD4 and CD8 cells among NOD, BALB/c, and C57BL/6 mice were not related to
modifications in the level of expression of adhesion molecules such as MEL-14, LFA-1, and
Pgp-1. 相似文献
18.
Dupont E Falardeau P Mousa SA Dimitriadou V Pepin MC Wang T Alaoui-Jamali MA 《Clinical & experimental metastasis》2002,19(2):145-153
A novel naturally occurring antiangiogenic agent isolated from cartilage, referred to as Neovastat (AE-941), was examined for its efficacy against tumor neovascularization and progression. Exposure to Neovastat results in ex ovo antiangiogenic properties in the chorioallantoid membrane of chicken embryo (71% decrease in the angiogenic index as compared to the basic fibroblast growth factor (bFGF) treated control embryos, P < 0.0001). Oral administration of Neovastat inhibits bFGF-induced angiogenesis in the Matrigel mouse model (87.5% decrease in hemoglobin as compared to the bFGF-treated control implants, P < 0.0001). Neovastat also induces a dose response decrease of lung metastases in the Lewis lung carcinoma model (oral administration; 69.1% of inhibition obtained at the maximal dose of 0.5 ml/day, P < 0.0001). Combined with a sub-optimal dose of cisplatinum (2 mg/kg, i.p.), Neovastat (0.5 ml/day) improved the therapeutic index by increasing the antimetastatic efficacy and by exerting a protective activity against cisplatinum-induced body weight loss and myelosuppression. In summary, our experimental data provide evidence of antiangiogenic and antimetastatic properties of Neovastat, following oral administration. 相似文献
19.
20.
Nguyen Khac F Waill MC Romana SP Radford-Weiss I Busson M Collonge-Rame MA Ribadeau-Dumas A Piffaut MC Daniel MT Davi F Merle-Béral H Berger R Arock M 《Cancer Genetics and Cytogenetics》2002,138(1):22-26
Two patients with Ph-positive chronic myelocytic leukemia in erythroblastic transformation and rearrangement of the short arm of chromosome 18 are reported. Fluorescence in situ hybridization studies showed that the 18p rearrangement resulted from translocation of the main part of chromosome 22 long arm to 18p, including BCR-ABL1 fusion. The 18p abnormality resulted, thus, in loss of 18p and duplication of BCR-ABL1 in both patients. The possible relation to the erythroblastic type of blastic phase is briefly discussed. In addition an apparently intact germline ABL1 gene was duplicated and inserted into chromosome 6 at band p21 in one of these patients. 相似文献